Flexible display technology has been developed rapidly in the recent decade and as a result, the flexible display device advances greatly from the size of the screen to the display quality. Flexible display device, also known as rollable display, is a rollable and deformable display apparatus which comprises a visible flexible panel made of flexible materials. Both the CRT which could almost be on the brink of disappearance and the current mainstream LCD substantially belong to the traditional rigid display. Compared with the regular rigid display, the flexible display device has many merits, such as impact resistance, better anti-knock ability; small weight and volume, more convenient to carry; employing tape technology which is similar to the newspaper print technology, and lower cost. Depending on its rollable characteristic, the flexible display device is competent for all the fields wherein the traditional display device is applied and other many fields requiring a curved surface display device, such as a smart card, an electronic paper, a smart tag and, and the flexible display device shall occupy a huge share in the future display product market, thanks to its outstanding properties.
The existing method for manufacturing a flexible display device generally comprises: a step of forming a releasing layer on a carrier substrate, a step of forming a flexible substrate on the releasing layer, and a step of fabricating a display device on the flexible substrate, wherein the flexible substrate is generally formed by applying liquid polyimide on the carrier substrate. The common solvents for the liquid polyimide such as 1-methyl-2-pyrrolidone, butyl cellosolve, etc., are relatively weak in infiltration on the glass carrier substrate, which easily causes holiday of the liquid polyimide on the surface of the glass carrier substrate. The holiday of the liquid polyimide at the juncture of the glass carrier substrate and the releasing layer leads to defects of the polyimide membrane substrate such as warp, bubble and peeled off undesirably during the fabricating of the flexible display device, and therefore will reduce qualified rate of the flexible display device.